CONTENTS 



PART I. GENERAL DEVELOPMENT 



CHAPTER I 



THE GERM CELLS i 



The Ovum i 



The Spermatozoon 6 



References for Further Study 10 



CHAPTER II 



MATURATION n 



Spermatogenesis Maturation of the Sperm 1 1 



Maturation of the Ovum 16 



Significance of Mitosis and Maturation 20 



Sex Determination 21 



Ovulation. 23 



References for Further Study 26 



CHAPTER III 



FERTILIZATION 27 



Significance of Fertilization 33 



References for Further Study 34 



//EAR 



CHAPTER IV 



ARLY DEVELOPMENT OF AMPHIOXUS 35 



Cleavage 35 



Gastrulation 38 



Mesoderm Formation 42 



References for Further Study 47 



CHAPTER V 



EARLY DEVELOPMENT OF THE FROG 49 



Cleavage 51 



Gastrulation 55 



Mesoderm Formation .....* 59 



References for Further Study 65 



vii 



